Expert Interview New Paths in 3D Printing
Additive manufacturing: In industrial 3D printing, Siemens plays a leading role worldwide. The group also owes this to its on-campus center at the RWTH Aachen, where new paths are opening up in 3D printing.
The way Siemens research staff are being inspired here by the Fraunhofer Institute for Laser Technology (ILT) and the Digital Photonic Production (DPP) research campus can be seen in this report by Dr. Thomas Neuenhahn, Head of Manufacturing Center of Excellence at Siemens, and doctoral student Hamid Jahangir.
Dr. Neuenhahn, how did you get into additive manufacturing and come to lead the Siemens team on the Aachen campus?
Neuenhahn: As a machine construction graduate with a subsequent doctorate in aerospace from the RWTH Aachen, I already had established links with the RWTH Aachen. After extensive work and study in Australia, Russia and China, I returned to Germany and then, in 2016, to Aachen in order to set up the Siemens Campus Research Team there. This partnership with the RWTH Aachen and the Fraunhofer Institutes ILT and IPT is part of my task as leader of innovation management for the Power & Gas Division. This department, together with the specialist group Additive Manufacturing (AM), is driving forward the technology planning and pre-development. This work was my first contact with additive manufacturing and, as a former development engineer for turbine blades, I was fascinated by the constructional freedoms of AM.
What role is played by the center in Aachen?
Neuenhahn: In the fields of AM and the closely related digitalised manufacturing, we employ 35 staff and students. We do fundamental development, particularly in close cooperation with the Fraunhofer ILT, a leader in AM questions and which I consider to be the reference address for 3D metallic printing. Situated in the Photonik cluster on the RWTH Aachen campus, the research campus DPP offers us perfect opportunities for cooperation and exchange with university institutes and other partners in industry, but also with start-ups. It is very practical for us, in that we can share technical equipment belonging to the DPP research campus and the RWTH Aachen. A great advantage of the campus is that the latest manufacturing technology is always available there. It is good, in my view, that technological development is moving ahead very fast thanks to networking with, for example, the Fraunhofer ILT.
Mr. Jahangir, you are concerned with “digitalization of additive manufacturing”, the subject of your doctorate. What value does AM technology have for you?
Jahangir: I studied mechatronics in Pakistan and, in Aachen, management and engineering of production systems. Since 2017 I have been working, as a Master of Science, in the AM department at Siemens, where I am also based for my doctorate on “process monitoring for the LPBF 3D printing process” (a 3D metallic printing process originally invented by Fraunhofer ILT, also known as selective laser melting or SLM). I am particularly fascinated by the creative possibilites in design and the high degree of freedom in the production process. In addition, this technology is perfectly suited to Industry 4.0 because of the digitalisation.
Siemens is internationally active in the field of additive manufacturing: what role does Aachen play here?
Neuenhahn: We can cover the entire technological development, meaning that we accompany the entire process from the idea to the industrialisation of the manufacturing technology. The central focus here is on research and development as an important building block within the Siemens network. We use in-house 3D printing for prototypes in order to boost the performance and efficiency of gas turbines and thus contribute to decarbonising, that is, to the reduction of carbon dioxide emissions.
Mr. Jahangir, how do you, as doctoral student, get involved?
Jahangir: Currently, I am responsible for monitoring the laser power bed fusion (LPBF). I am developing a system for analysing image and sensor data which uses intelligent algorithms to discover faults in structures. In this way, it is possible to develop strategies for avoiding errors in building up layers. Because the monitoring is done directly during the 3D printing, it is possible to eliminate later and time-consuming quality assurance, such as expensive computer tomography.
What is the situation with handling the large quantities of data arising during these processes, that is, how do you deal with big data?
Jahangir: We collect data from the 3D installations at the various locations in the Siemens AM network so that we can then analyse them centrally.
What distinguishes the various Siemens AM locations, what are their specialities, and how does Aachen support them?
Jahangir: With Berlin, we help them by improving the manufacturing process for prototypes. The methods introduced there and the resulting advances are helpful for other locations, such as those in England and Sweden, in optimising their processes. These scientific solutions and their transfer to industrial processes in Berlin are carried out in close cooperation with university facilities on the campus. In turn, Berlin gives us feedback on how our solutions stand up in practice. If they are received positively in Berlin, knowledge is then transferred to the other locations. Berlin thus serves as a kind of validation platform.
Dr. Neuenhahn, in which areas, other than 3D printing, do you cooperate directly with the Fraunhofer ILT?
Neuenhahn: We have developed jointly a laser process for creating cooling-air bores in turbine blades. With the laser, it is possible to produce not only round, but also complex forms of bores which improve the outflow of cooling air into the hot gas stream in the turbine section. The result is that a layer of air is formed around the turbine blades, protecting them from the hot gas coming from the combustion chamber at over 1500 °C. This measure reduces the proportion of cooling air required and thus improves the efficiency and performance of the gas turbine.
What is happening on the digitalisation front?
Neuenhahn: Here we are likewise collaborating closely with the Fraunhofer ILT on applications for all aspects of Siemens’ Mindsphere driver for the Internet of Things: within the Photonik cluster, for example, there is the Siemens Mindsphere Lounge in which scientists and students can network and use the latest IoT technology for realising their ideas and developments in Mind Apps. This enables current research in the community to be presented and marketed.
Where does it go from here?
Neuenhahn: In future, more components for the combustion chamber area in turbines will be printed in 3D. Many developments in this field are based on activities in Aachen: years ago, we printed the first blade for a large gasturbine in Aachen. On top of that, three years ago, we cooperated with the Fraunhofer ILT to start a student competition for better cooling of 3D-printed turbine blades. The ideas arising from that are now being incorporated into design concepts; one example is a 3D-printed ring segment for the intake area of the turbine section, that is, where the hot gases from the combustion chamber, at over 1500 °C, meet the turbine blades. This ring segment has already been tested successfully in the turbine section of a large gasturbine in Berlin. This was the world’s first 3D-printed component in the turbine section of a large gasturbine. These joint activities are valuable not only for discovering ideas, but also for attracting students and scientists knowledgeable in additive manufacturing and digital production. This is a further reason for making intensive use of our research and development in Aachen.
How do you see the collaboration with the Fraunhofer ILT, what help has it been to you, how does the “campus spirit” influence you?
Neuenhahn: Here it has been possible for us to assemble very quickly a lot of competence on the topic of additive manufacturing and to achieve a corresponding leading position in technology in this field. The DPP research campus helps us in the transfer of knowledge between industry and research. We have greatly benefited from the joint consortium projects, such as those linked to the International Center for Turbomachinery Manufacturing, in which we jointly sound out the possibilities of, for example, additive manufacturing in turbine construction. They have already helped us greatly in achieving our goals.
Mr. Jahangir, what impression do you have of life on the campus, is it a kind of Silicon Valley for manufacturers?
Jahangir: For me it is clear that Aachen is well on the way to becoming the Silicon Valley of production technology. One pointer for this is that it already has many features in common with California and the kind of collaboration found there.
“In future, more components for the combustion-chamber area in turbines will come from 3D printing.” - Dr. Thomas Neuenhahn, Head of Manufacturing Center of Excellence, Siemens.